Improvement in disintegrating fibrous substances for paper-pulp



A. s. L YMAN. Y I s for Paper Pulp..

Dis integrating Fibrous Substance Patented-Junel6,1874.

UNITED STATES PATENT @rrron AZEL STORES LYMAN, OF NEW YORK, ASSIGNOR TOADDISON H. LAFLIN, OF HERKIMER, NEWV YORK.

IMPROVEMENT IN DISINTEGRATING FIBROUS SUBSTANCES FOR PAPER-PULPSpecification forming part of Letters Patent No. 1 51,991, dated June16, 1874; application filed April 16, 1574. i

To all whom it may concern:

Be it known that I, AZEL SToRns LYMAN, of the city, county, and State ofNew York, have invented a new and useful Improvement in the Art ofDisintegrating Fibrous Sub stances, of which the following is aspecification:

, This invention relates to the disintegration of wood, straw, hemp,flax, cotton, wool, and other fibrous substances in the manufacture ofpaper and for other purposes; and its main object is. to secureuniformity in the fiber produced, and at the same time preserve itsstrength and elasticity, a secondary object being economy of power,conjoined withrapidity of operation and a consequent diminution in thecost of production. The invention consists, in general terms, inimmersing or mingling the stock, whether rags, straw, wood, or otherfibrous substance, with water or any other suitableliqnid, andsubjectingit to the action of rapidly-moving pickers or strikers in sucha way that the requisite resistance to the blows of the pickers isfurnished by the inertia of the material itself, and of the medium inwhich it is carried. In the rag-engine, as ordinarily constructed forbeating out paper-stock, some stationary structure, generallydenominated a bed-plate, is opposed to the beating roll or cylinder,underneath the same, in such a way that the stock is caught between theknives or ribs of the bed-plate and the fly-bars or knives of the rollin the revolution of the latter. In such machines the metallic ribs ofthe bed-plate furnish the resistance, by means of which the knives ofthe roll are enabled to cut and abrade the stock, and thus graduallyreduce it to fiber.

But for this resistance afforded by the bedplate, or some equivalentresisting surface, it would be impossible for the beating-roll of theordinary rag-engine to do efiective work. As its knives are constructedwith a continuous edge they are not adapted for penetrating theinterstices of the stock; and further, being arranged upon the peripheryof the roll, muchafter the manner of the blades upon the periphery of apaddle-wheel, the great resistancethey necessarily encounter in passingthrough the water absolutely prevents such rapidity of movement as wouldbe required to reduce the stock, if at the moment of impact it had noother support than that of the liquid medium in which it was floating.The action, moreover, of the ordinary engine, in which the material iscaught between theribs of the bed-plate and the knives of the roll, isto crush and bruise, and to break and cut the fibers, and thusmaterially. impair their strength. A similar result, although'perhapsincreased in degree, attends the use of all those processes for theproduction of paperpulp, in which the raw material is subjected to theaction of grinding surfaces, whether such surfaces are smooth orcorrugated or otherwise roughened. By all such processes, also, thefibers will be crushed or bruised and broken, so as to take from theirnatural strength.

By the improved process, now for the first time discovered, it isproposed that at the moment when the blows of the pickers are de liveredupon the stock to be reduced, the stock shall have no other support thanthe liquid in which it is held in suspension; and as thus the onlyresistance that is afforded to the blows of the pickers will be theinertia of the stock itself and of the unstable liquid in which it isimmersed, it is found advisable so to form the pickers that they willstrike into or penetrate the stock as well as strike upon or against it,and absolutely essential so to construct and arrange them that they canbea run with a high velocity. To this end it ispreferred to use forpickers or strikers a series of points or of teeth, both because of theefficiency with which points and teeth can be made to attack the stockto be reduced, and because of the ease with which they can be driventhrough the water. Again, in order to secure the requisite velocity foreffective work, it will be found advisable so to locate the pickers thatthey will act upon the stock at or near the surface of the liquid inwhich it is moving, since thus the pickers will merelydipinto the waterwithout being submerged. The larger the proportion of thepicker-mechanism that is exposed above the water, the lighter andconsequently the faster'it can be run.

A fiber -'reducing engine embodying the principle of this improvedprocess is not necessarily limited to any particular form or dimensions;these will be determined mainly by the character and amount of work tobe performed. Various devices also may be employed for producing therequisite circulation of the material to be acted upon, and the pickersor strikers may be variously constructed, care only being had that theybe made to move with such velocity, and that their operative parts be soformed and so arranged with relation to the other parts of the engine asto separate the fibers by a picking, snapping, whipping, or tearingaction, as contradistinguished from grinding, cutting, or abrasion.

The process, again, according to the nature of the stock to be worked,may be carried on in an open vat or in a closed chamber, and underpressure, thelatter mode of working it being specially adapted for themore refractory substances, which may be found to require a hightemperature to fit them for the most eificient action of the pickers.

It is not proposed, therefore, to limit the invention to any particularform or dimensions in the construction of the engine, since them..-vent-ion consists in a process rather than in The accompanying drawingsshow the application of the invention to a closed engine.

The modifications of structure that accompany its application to theordinary open-vat pulp-engine are designed to form the subject of aseparate patent, application for which is made of even date herewith.

Referring to the accompanying drawing, Figurel is a vertical section onthe line a; w of Fig. 3. Fig. 2 is a vertical section in a plane atright angles to that of Fig. 1, and Fig. 3 is a horizontal section justabove the feed-screw.

'The engine here represent-ed consists of a cylinder, of iron or othersuitable metal, six feet in diameter and eighteen feet in height, or itmay have such other dimensions as may be deemed expedient, and it shouldbe of sufficient strength to withstand the required internal pressure.Of course it should be provided with a safety-valve with steam-gages andother appliances necessary upon ordinary steam-boilers. This cylinder isset in a vertical position, and is divided throughout the greater partof its height by a diaphragm, forming it into two compartments, which,however, communicate with the each other at the top and the bottom, asshown in the drawing.

In the upper part of the cylinder and over the right=hand compartmentare arranged the pickers or strikers. In the space beneath thediaphragm, and arranged at right angles to the plane thereof, is placeda shaft, upon which are supported one or more propeller-blades, whichare designed for feeding the material through from one compartment tothe other. Surrounding the first-named cylinder and com centric with itis another of somewhat large diameter, and extending up to about thelevel of the lower part of the pickers.

The space between the two cylinders is designed as a hot-air flue. Byplacing vertical flue-strips in this annular space, in the plane of thediaphragm before spoken of, and building a fire under. the bottom of theright-hand compartment, the smoke pipe being at the same time placed onthe other side of the fluestrips and near the bottom of the annularspace, the heated products of combustion will be caused to ascend incontact with the wall of the right-hand compartment and descend alongthe wall of the left-hand compartment, and thus, as the currents withinthe cylinder are ascending on the right of the diaphragm and descendingon the left, the heat can be made not only to increase the temperatureof the water, but also, to some extent, to assist the circulation.

The pickers here shown are a gang of disks arranged upon a shaft abovethat compartment in which the currents are ascending, the peripheries ofthe disks being armed with long teeth. These saw-toothed disks are ofthin metal, preferably of steel, and by means of collars are adjusted ata distance of about seven-eighths of an inch apart. The teeth'are bentlaterally at various angles of inclination, so that, when moving, theseveral paths will, so far as possible, be out of the same line oftravel. The edges of the teeth are notmade sharp enough to cut thefibers, but the points are so constructed as to pick and pull or tearthe fibers apart, thus leaving them much stronger than if they had beencut or broken by grinding or abrasion between antagonizing surfaces.These pickers are so arranged at the top of the right-hand compartmentas to dip but partially into the surface of the water, and thus they canhave imparted tothem a much higher velocity than would be possible werethey submerged, and, it is believed, can thus be made to act moreuniformly upon all parts of the pulp.

Both the pickers and the feed-screw may be operated by connection withany suitable motive power, the connection being effected in any of thewell-known modes.

In the top of the cylinder is a man hole, provided with a cover, and adischarge orifice or orifices for drawing off the charge may be providedat any convenient point in the side or bottom of the cylinder.

Referring to the drawings, A represents the main cylinder B, thejacketing-cylinder; O, the diaphragm; vD, the pickers; E, the screw;

. F, the fire chamber and grate; G G, the fluestrips; H, the smoke-pipe5and J, the man hole. S is a pipe, by means of which steam may at anytime be admitted to the cylinder.

The operation of this engine is as follows: After the cylinder is filledwith water to the requisite height, the cut wood or other-material ispoured in by the manhole while the engine is at rest, or is runningslowly. The' man-hole isthen closed and the speed of the engineincreased,'when the revolution of the pickers in the direction of thearrows draws the fibrous material and the water away from belowandthrows it up over the upper part of the. diaphragm or septum, intothe left hand-compartment, where it descends to the lower aperture inthe diaphragm, through which it returns to its starting-point, and thusit is kept in constant circulation and is rapidly pickedv to pieces.

This circulation, as already indicated, may be aided by the screw-bladedshaft placed in the bottom of the cylinder; but any other suitabledevice for the same purpose may besubstituted for this, or it may bewholly omitted and still a sufficient circulation for most practicalpurposes be maintained by the combined action of the revolvingpickersand the gravity of the material.

\Vhen wood and other refractory substances are being treated, steam maybe let on by the pipe S below, and this, blowing up the righthand sideof the diaphragm, accelerates the The steam also contributes tocirculation. create and maintain the requisite temperature and pressure.

\Vhen the temperature ard corresponding pressure are raised to therequisite degree to dissolve the sileX, the pickers are to be run veryrapidly until the material is thoroughly reduced. The knots, on account'of their greater inertia, are torn to shreds and reduced to theirultimate fibers as quickly as any other part of the material, and in allcases the largest pieces are acted on with the greater violence, theresult of which is a marked uniformity in the pulp produced. So far asconcerns the principle involved in this operation,

it is manifest that the two compartmentsin which, respectively, thestock is ascending and descending, instead of being separated by asimple diaphragm, may be placed at agreater distance apart, provided,only, that they are constructed with suitable connecting trunks orconduits at the top and bottom. Thepickers, whether in the closedchamber or in the open vat, will ordinarily be run with a speed of fromfive thousand to eight thousand feet per minute, and as the resistanceto their blows is furnished by the inertia of the material, as supportedin a fluid of great mobility, it is evident that a high speed isabsolutely essential before the pickers can become efficient inseparating the fibers. It is found in practice that with the substancesat present used for paperstock, the pickers must be made to move at arate of not less than from about twenty-five hundred to three thousandfeet per minute, which is very largely in excess of the speed of thebeating-roll in an ordinary pulpeengine.

In the closed engineshown in the drawing, the relative position of thepickers and the water is much the same as that of an undershotwater-wheel to the stream by which it is driven; and this relativeposition will be main-- tained in applying the invention to the ordinaryopen-vat pulp-engine. Substantially the same principle of 7 operation,however, would be involved if the water which carries the stock weremade to flow against the side or upon the top of the structureconstituting the picker mechanism, after the manner of breast-wheels orovershot-wheels. In such cases it would probably be found necessary tocause the pickers to revolve in the reverse direction from ordinarybreast or overshot millwheels when driven by the current, in order toprolong the contact of the pickers with the stock; but the reduction ofthe stock would still be effected by the percussive and tearing actionof the picker-points, and not by the grinding, abrading, or cuttingaction. heretofore relied upon in the engines in which the reduction hasbeen effected by mechanical means. The pickers, whether working in thecommon open vat or in a closed vessel, do not 7 cut the fibers in piecesor grind and injure them, as the common mills do; but they pick,

whip, and snap them out with but little waste of their strength. All' ofthe beating and grinding processes heretofore in vogue tend,

more or less, to bruise, break, cut, and pulverize the fiber. The newprocess, on the contrary depends entirely upon the percussive andtearing action of the pickers or strikers, which are so constructed, andso arranged in relation to the other parts of the mechanism, as whollyto avoid the grinding action of opposingsurfaces, as well as the cuttingand abrasion produced by the action of blades revolving over" or againstother and resisting blades or surfaces, in such a way that the materialis caught between the two sets or series of blades, and thereby cut orshredded to pieces.

The present invention is distinguished from that for which a patent wasgranted Azel Storrs Lyman on the 4th day of March, 1862, entitled animproved process of separating the fibers of wood and other substancesfor the manufacture -of paper pulp, in which there was showna series. ofso-called beaters, that revolved in contact with the material-to bereduced. Not only the construction and the arrangement, but the functionof the heaters there shown was essentially different from that of thepickers employed in the present invention. The primary function of thoseheaters was simply to feed the material to the cone-shapedgrinding-mill,and for this purpose they were arranged spirally upon theshaft of the grinding-cone. This function also required that they shouldbe entirely submerged, so that, even if made of different shape, itwould have been next to impossible to give them suflicient rapidity ofrevolution to render them efficient to reduce the material. a form leastadapted for disintegrating the substances from which paper-pulp isproduced. In all these particulars the present invention is materiallydifferent from anything described or known in the patent named. By theformer They were also made with blunt edges,

process, the stock was to be reduced by the grinding-surfaces, whichconstituted a part of the mechanism shown. B y the present process, thework is' done by the percussive and tearing action of the pickers, thestock having no other support when the pickers strike it than What isafforded by the yieldin g fluid in which it is floated.

WVbat I claim as new is- 1. The process hereinbefore described ofdisintegrating fibrous substances, the same consisting essentially insubjecting them, while held in suspension in or mingled with Water orother liquid, to the percussive and tearing action of rapidly-movin gpickers or strikers, the

resistance to the blows of which is furnished by the inertia of thematerial under treatment, and of the medium in which it is moving.

2. A fiber-reducing engine, constructed with two vertical compartmentsor trunks which communicate at top and bottom, as set forth, and one ofwhich is provided with a series of pickers or strikers, constructed andarranged to operate substantially as and for the purpose described.

AZEL STORES LYMAN.

Vvitnesscs:

SAML. A. DUNCAN, BENJ. A. SMITH.

